Who has to comply with ESOS?

A large undertaking, tested at 250 or more UK employees on its own, or turnover above £44m together with a balance sheet total above £38m. Your position on the qualification date of 31 December 2026 decides whether you are in scope for Phase 4.

What is the ESOS Phase 4 deadline?

5 December 2027. The compliance notification must reach the Environment Agency, or the devolved nation equivalent, by then, through MESOS.

We qualified for Phase 3. What is due now?

Your final Phase 3 progress update is due by 5 December 2026, signed off by a board level director and submitted through MESOS. It needs the savings data and implementation evidence that Phase 4 will ask for again.

Does one subsidiary bring the whole group in?

Yes. If any single UK entity in a corporate group meets the test, every UK entity in that group is brought into scope, including ones individually well below the threshold. This is the point most often missed.

Is ESOS the same test as SECR?

No. ESOS is 250 or more employees on its own, or both financial thresholds together. SECR is two of three thresholds. The same company can sit inside one regime and outside the other, so both need checking on your actual figures.

What does ESOS support cost?

The initial review, which establishes whether you are in scope and what data you hold, costs nothing. The assessment work itself is quoted and agreed in writing before it starts, and the lead assessor requirement is set out in that quotation.

Services

ESOS Phase 4 compliance

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Phase 4 cycle

The cycle runs on fixed dates, not on reminders.

Select a point on the cycle to see what it decides and when it falls.

31 Dec 2026Qualification date

Your position on the qualification date decides whether you are in scope for Phase 4.

Phase 4

Take control with Omnium

Know plainly whether ESOS applies, and what has to be filed.

Qualification, audit and filing scoped to your estate, read against the published scheme timetable.

Qualification checked, not assumed
We work out whether your organisation actually meets the ESOS thresholds.
Audit scoped to your estate
The audit reflects your sites and your meters, not a generic exercise.
Phase deadline on the calendar
The filing deadline sits on the same calendar as the rest of your compliance dates.
Plain-English scheme explainer
A working guide to the scheme, drawn from what we publish, with the source named.

Where it goes wrong, and what we do about it

How Omnium solves it
We work out whether you qualify, and say so plainly, before any audit work is scoped or charged.
How Omnium solves it
The audit is scoped to your sites and your meters, so the findings and the filing reflect what the estate actually does.
How Omnium solves it
The ESOS phase deadline is held on the same calendar as the rest of your compliance obligations, so it does not depend on one person remembering.

Questions

Who has to comply with ESOS?: A large undertaking, tested at 250 or more UK employees on its own, or turnover above £44m together with a balance sheet total above £38m. Your position on the qualification date of 31 December 2026 decides whether you are in scope for Phase 4.
What is the ESOS Phase 4 deadline?: 5 December 2027. The compliance notification must reach the Environment Agency, or the devolved nation equivalent, by then, through MESOS.
We qualified for Phase 3. What is due now?: Your final Phase 3 progress update is due by 5 December 2026, signed off by a board level director and submitted through MESOS. It needs the savings data and implementation evidence that Phase 4 will ask for again.
We did not qualify last time. Are we safe?: No. Qualification is assessed afresh each phase, so not qualifying before does not carry forward. An organisation that missed the Phase 3 snapshot on 31 December 2022 may qualify now after four years of growth.
Does one subsidiary bring the whole group in?: Yes. If any single UK entity in a corporate group meets the test, every UK entity in that group is brought into scope, including ones individually well below the threshold. This is the point most often missed.
Is ESOS the same test as SECR?: No. ESOS is 250 or more employees on its own, or both financial thresholds together. SECR is two of three thresholds. The same company can sit inside one regime and outside the other, so both need checking on your actual figures.
What does ESOS support cost?: The initial review, which establishes whether you are in scope and what data you hold, costs nothing. The assessment work itself is quoted and agreed in writing before it starts, and the lead assessor requirement is set out in that quotation.

Read the detail

How to check this

Each claim on this page is answered by something you can read for yourself. Nothing below states a figure; it names the document or register the claim is held against.

Point 01
We hold a Level 1 Letter of Authority only
The authority wording sets out what we may do with your data and states that we cannot sign a contract on your behalf. Read it before you sign it.
Read the Letter of Authority
Point 02
How we are paid is agreed in writing before you sign
Our margin or management fee is stated in the terms that accompany a recommendation, and nothing is added afterwards.
Client terms and conditions
Point 03
Every figure we quote carries a dated source document
Records state the figure, what it is measured against, the document it is taken from and the date on that document. Records still held anonymous are labelled as such.
Evidence records
Point 04
Compliance work is held against the current legislation
Each obligation is recorded with the rule it comes from and the deadline it carries, in an evidence pack an auditor can follow.
Compliance
Point 05
We work to a published code of conduct
Our obligations as a third party intermediary, and what you can hold us to, are set out in full.
Third party intermediary code

Ask about ESOS

Put a question about the scheme and get a plain-English explanation drawn from what we already publish, with the source you can check named. It reads our compliance pages and sheets, and nothing else.

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Proof

What we have delivered, and who checks our work.

Each figure below is taken from our evidence record and has a full case study behind it.

Michels and Taylor
£206,000a year saved on procurement
Read the case study: Michels and Taylor
Broadening Choices for Older People
£161,000a year saved on gas, about £483,000 across a three-year term
Read the case study: Broadening Choices for Older People
Roam
Group rates10 per centlower than the previous brokered prices
Read the case study: Roam